Prediction of soot particle size distribution for turbulent reacting flow in a diesel engine

Abstract

There is increasing interest in obtaining the size distribution as well as the number density and mass fraction of soot particles created by diesel engines. This study addresses this problem and particle size distributions are computed and validated in typical operating conditions of a diesel engine. The program KIVA is modified and integrated with CHEMKIN in order to be able to consider detailed gas phase kinetics and soot precursors using the conditional moment closure (CMC) model for turbulence/chemistry coupling. The soot simulator, SWEEP is then used to calculate the size distribution as a post-processing step at any given mixture fraction. The conditional results obtained at a mixture fraction of 0.12 are generally consistent with measurements over a range of engine operating conditions. However, the effect of differential diffusion in the probability density function weighted quantities affects the quality of the results obtained as a function of engine speed.